1. Field of the Invention
The present invention relates to a substrate with a pixel structure and a fabricating method thereof, and a liquid crystal display panel and liquid crystal display with the substrate, and more particularly relates to a substrate with a multi-domain vertical alignment (MVA) pixel structure featured by a low color shift (LCS) and less dark fringes and a fabricating method thereof, and a liquid crystal display panel and liquid crystal display with the substrate.
2. Description of Related Art
An LCD display has the characteristics of high picture quality, high space efficiency, low power consumption, no radiation and so on. Currently, the following types of LCD display with a good display effect have been proposed, such as IPS (in-plane switching) LCD display, FFS (fringe field switching) LCD display, MVA (multi-domain vertical alignment) LCD display and PSA (Polymer-stabilized alignment) LCD display and so on.
FIG. 1 is a schematic cross-sectional view of a multi-domain vertical alignment liquid crystal display panel. Referring to FIG. 1, the multi-domain vertical alignment liquid crystal display panel 100 includes a first substrate 110, a pixel electrode 120, a liquid crystal layer 130, a common electrode 140, a color filter layer 150 and a second substrate 160. It should be noted that, a slit S is disposed on the pixel electrode 120 and the common electrode 140 and the formed electrical field E is bent under the influence of the slit S. Therefore, liquid crystal molecules 132 are inclined towards different directions to form a distribution of a plurality of regions, thereby achieving a display effect of wide viewing angle. However, this multi-domain vertical alignment liquid crystal display panel 100 needs a precise alignment of upper and lower slits S. Otherwise, once the alignment error between upper and lower slit S is generated, the alignment region is uneven and the light transmittance is reduced.
FIG. (1) and FIG. (2) of FIG. 2A are schematic top views of a multi-domain vertical alignment liquid crystal display panel respectively. FIG. (1) and FIG. (2) of FIG. 2B are schematic cross-sectional views of the multi-domain vertical alignment liquid crystal display panel in FIG. (1) and FIG. (2) of FIG. 2A taken along Line I-I′ respectively. FIG. (1) and FIG. (2) of FIG. 2C are schematic top views of pixel electrodes 120, 120′ of the multi-domain vertical alignment liquid crystal display panel in FIG. (1) and FIG. (2) of FIG. 2A respectively. FIG. (1) and FIG. (2) of FIG. 2D are schematic top views of pixel electrodes 122, 122′ of a multi-domain vertical alignment liquid crystal display panel in FIG. (1) and FIG. (2) of FIG. 2A respectively.
Referring to FIG. (1) of FIG. 2A to FIG. (1) of FIG. 2D, the components of the multi-domain vertical alignment liquid crystal display panel 200 are the same as those of the multi-domain vertical alignment liquid crystal display panel 100, so the components are indicated by the identical symbols.
It should be noted that in the multi-domain vertical alignment liquid crystal display panel 200, two layers of the pixel electrodes 120, 122 with the slit S are fabricated on the same side instead of fabricating the slit S on the common electrode 140. A protection layer 170 is additionally disposed between the pixel electrodes 120, 122. This method can solve the problem of alignment error, but the structure with the slit S may generate the dark fringe to reduce the light transmittance.
To reduce the number of dark fringes of the multi-domain vertical alignment liquid crystal display panel, another multi-domain vertical alignment liquid crystal display panel 200′ is provided in the prior art. Referring to FIG. (2) of FIG. 2A to FIG. (2) of FIG. 2D together, the components of the multi-domain vertical alignment liquid crystal display panel 200′ are the same as those of the multi-domain vertical alignment liquid crystal display panel 200, so the components are indicated by the identical symbols. In the multi-domain vertical alignment liquid crystal display panel 200′, the configuration of the pixel electrodes 120′, 122′ can reduce the number of dark fringes.
The aforementioned multi-domain vertical alignment liquid crystal display panels 200, 200′ respectively use two thin-film transistors 210, 220, 210′, 220′ to drive the pixel electrodes 120, 122, 120′, 122′. For example, in FIG. (1) of FIG. 2B, the thin-film transistor 210 is connected to the pixel electrode 120 and the thin-film transistor 220 is connected to the pixel electrode 122. In more details, the thin-film transistor 210 applies a low voltage (VL) to the pixel electrode 120 to form dark area and the thin-film transistor 220 applies a high voltage (VH) to the pixel electrode 122 to form bright area. Whereby, the multi-domain vertical alignment liquid crystal display panel 200 generates a display effect of a low color shift. However, in regard with the manner of using two thin-film transistors 210, 220 to drive two layers of pixel electrodes 120, 122, the driving design is complicated, and more number of the thin-film transistors 210, 220 is required, which causes the increase of the fabricating cost.
In addition, as shown in FIG. (1) of FIG. 2A, the multi-domain vertical alignment liquid crystal display panel 200 mainly uses a zigzag elongated pixel electrode pattern J to control an inclining direction of the liquid crystal molecules 132. However, a fringe field of the zigzag elongated pixel electrode pattern J cannot completely cover the slit S region, so the region with the slit S may present an optical performance of dark fringes. Although the processing method may be adopted to increase the width of the elongated pixel electrode pattern J (downsizing the slit S) and further improve the fringe field of the elongated pixel electrode pattern J, currently, the process width limit of the resolution and the etching process capability of the exposure machine is 3.5 μm, so the width of the elongated pixel electrode pattern J cannot be effectively increased in practice.
FIG. 3 is a schematic cross-sectional view of another multi-domain vertical alignment liquid crystal display panel. Referring to FIG. 3, the multi-domain vertical alignment liquid crystal display panel 202 includes a first substrate 110, a protection layer 170, a first pixel electrode 122a, a second pixel electrode 122b, a liquid crystal layer 130, a common electrode 140 and a second substrate 160.
In consideration of a low color shift, the distribution of bright and dark areas must be formed. To achieve a good light transmittance, normally the pixel electrode is sliced into the first pixel electrode 122a and the second pixel electrode 122b distributed in the left and right or the up and down, which are respectively applied with the high voltage (VH) and the low voltage (V). However, the electrical field E formed at the slit S between the first pixel electrode 122a and the second pixel electrode 122b makes the liquid crystal molecules 132 at the slit S inclined into the opaque status. Therefore, three dark fringes are generated at arrow A (three positions) in FIG. 3A, which reduces the display quality of the multi-domain vertical alignment liquid crystal display panel 202.